466 resultados para 66-2
Resumo:
A substantial strengthening of the South American monsoon system (SAMS) during Heinrich Stadials (HS) points toward decreased cross-equatorial heat transport as the main driver of monsoonal hydroclimate variability at millennial time-scales. In order to better constrain the exact timing and internal structure of HS1 over tropical South America we assessed two precisely dated speleothem records from central-eastern and northeastern Brazil in combination with two marine records of terrestrial organic and inorganic matter input into the western equatorial Atlantic. During HS1 we recognize at least two events of widespread intensification of the SAMS across the entire region influenced by the South Atlantic Convergence Zone (SACZ) at 16.11-14.69 kyr BP and 18.1-16.66 kyr BP (labeled as HS1a and HS1c, respectively), separated by a dry excursion from 16.66-16.11 kyr BP (HS1b). In view of the spatial structure of precipitation anomalies, the widespread increase of monsoon precipitation over the SACZ domain was termed 'Mega-SACZ'.
Resumo:
in preparation
Resumo:
Aliphatic and polycyclic aromatic hydrocarbons were examined in the surface layer of bottom sediments from the eastern part of the Sakhalin Island shelf (materials were sampled in summer 2002). Concentrations of hydrocarbons were determined to know changed since beginning of development of oil fields (compared with earlier years). According to distribution of markers in hydrocarbon compositions, bottom sediments are dominated by allochthonous (terrigenous) hydrocarbons that are the most stable compounds. Occurrence of transformed anthropogenic oil alkanes that have never been found before may be indicative of increasing pollution in the region.